Thursday, May 12, 2016

Sweating the SMALL small stuff

Everyone, I expect, knows about the guy (his name now forgotten) who said the key to a stress-free life is, Rule 1: Don't sweat the small stuff, and Rule 2: It's ALL small stuff.

He was a genius, and I try to live by those rules. But when I came to write a blog that would concern itself mainly with insects and other small creatures, I called it "Sweating the small stuff," and thought that was rather clever, until I looked into it and discovered about forty people had already used that name for their blog.

Anyway, lately we seem to have been looking at smaller and smaller stuff. It started when I got a new camera and macro lens set-up, a step up from my last one, and to try it out went around the garden taking pictures of every small thing I could find. It started with this honey bee, coming to a spiderwort.

I downloaded this picture, then put it to the test: I blew it up until just the bee filled the whole frame.

I was very pleased that the image could keep so much sharpness after being enlarged so many times.

Then (I was out with Cheryl) we saw a tiny thing that looked like an ant trundling along. If the bee was, let us say, 10 mm long, this new thing was closer to 5 mm long. When we looked really closely, we saw it was actually a jumping spider mimicking an ant. Here it is blown way up so you can see it more clearly.

An ant has six legs and a pair of antennae; a spider has eight legs and no antennae. But this spider is walking on its back six legs, and is waving its front legs in front of it to simulate antennae. Very clever, but why would a tiny spider imitate an ant? Well, ants are full of formic acid, which means they don't taste very good, so most things leave them alone.

Anyway, to get on with small things, Cheryl has an old pot in the front yard full of radish seedlings, and with her sharp eyes spotted some things in them that she had to point out several times before I could see them. Here's the pot. If you look carefully, you might see some little whitish dots sticking to the stems.

Here, from closer up, is what Cheryl saw.

We knew what these were right away. The pot had been overrun with aphids, but now the aphids were virtually wiped out. Tiny parasitic wasps (we're talking really tiny now, 1.5 mm) had visited them, and with their sharp ovipositors had injected an egg into each aphid. The egg hatched into a wasp grub, and the grub fed on the aphid. To show you how small the grub was, that aphid provided enough food for that grub to grow to full size and form a pupa (all this inside the shelter of the aphid's outer skin). While the grub was feeding, the aphid turned brown, which made it easy to see which ones had been parasitized.

Here is the scene several sizes larger. On the top left are two healthy juicy green aphids, on the right brownish ones that are harboring feeding or already pupated grubs. One has a round hole in the top, marking where a wasp had metamorphosed and chewed its way out.

Once we got our eye in, we noticed that the wasps were flitting all about. Making pictures and blowing them up helped us to see more of the action, though we are far from having everything figured out.

Here, for example, is one of the wasps. It's possible that it just emerged from the hole in the aphid beside it. Its fairly slender abdomen, its lack of an ovipositor, and its very long antennae make us believe it is a male. This is guess-work, but perhaps the long antennae are very sensitive to the alluring odors of females. Perhaps he can smell a female about ready to burst out of the aphid shell he is sitting on, and he is waiting around to make sure he gets first dibs. For the moment all the many wasps we see seem to be males, and perhaps it is timed this way to make sure each emerging female has a mate waiting for her. Otherwise it might be impossible for such tiny things in such an enormous world (millions of times bigger for them than for us) to ever find each other.

The wasps can't waste too much time sitting around, because they are themselves part of the stream of life, and are just right for slightly larger creatures to feed on. We see a half-grown jumping spider is already feeding on one.

Cheryl looks under a leaf that has spider webbing in it (her thumb and the nearby wasp will give you a sense of scale) and finds another spider that has a wasp wrapped up.

Perhaps you still can't see it; it's just down from the wrapped wasp, and a little to the left). It's not only minuscule, but has protective coloring. Here it is still larger.

Okay, one more try.

The next day a more serious threat appears. You know the big black and yellow garden spider that makes enormous webs in the corner of your yard. They are formidable hunters. Those that live over our pond feed mainly on tree frogs. Well, here's what they look like when they hatch from the egg, and they already have something magic in their web, ultra-violet coloring or something, because look how many wasps this one has caught in a single day.

And now we believe we have seen the most sinister predator of all.

We thought at first this was finally a female. Note the fat abdomen, the short ovipositor, the short antennae. But now we have seen it poking its ovipositor into the aphid shells. There is nothing inside those shells but the newly forming parasitic wasps. Besides, this wasp is marked differently from the male wasps. Is this a different species? Is this, in fact, a hyper parasite, a parasite upon parasites?

Who would have imagined a few shots with a camera and macro lens could open up a lifetime of studies.

1 comment:

About Sweating

My wife Cheryl and I have always loved everything to do with nature, but in the last ten or fifteen years we have been especially focused on insects. If the day is sunny, we grab our binoculars, our cameras, and take off for the wilds. Even on a poor day the marvels pile up quickly. A new season is just beginning. In this blog I mean to record the things we discover, the photos we take.